The age of Socrates was one of advancements in thought, art and politics—and sharp debates about democracy.

Two and a half millennia after an Athenian philosopher drank a poisoned cup of hemlock as punishment for crimes against the state, the ancient Greek world continues to captivate us. And rightly so: New scholarship continues to reveal just how remarkable it was. Most premodern states, like too many countries today, were dominated by a small elite of ultra-privileged insiders who monopolized public goods, skimming off whatever surplus was produced by populations living near bare subsistence and thus seizing super size shares of stagnant economies. By contrast, the Greek world in the 500 years from Homer to Aristotle saw sustained economic growth and historically low level of economic inequality. Recent studies suggest that, from 800 B.C. to 300 B.C., the population of the Greek city-states increased by a factor of 10, while per capita incomes roughly doubled. That growth rate may be sluggish compared to leading 21st- century economies, but it is amazing by the standards of premodernity. What can explain such economic growth? Free Greeks (we must never forget that this was a slave society) invested their efforts in industry, commerce and politics because they did not fear that the fruits of their effort would be expropriated by the powerful. Further, though the roughly 1,000 city-states of classical Greece competed fiercely in war, they actively exchanged goods and ideas. Among the productive innovations that spread rapidly across the Greek world were coinage, codes of law, and deliberative councils. There was no imperial center but instead a historically distinctive approach to politics.

The typical city-state was republican rather than autocratic, and a substantial part of the adult male population enjoyed participation rights. In Athens, the epoch-making "People's Revolution" in 508 B.C. resulted in democracy—the strongest form of republicanism the world had ever known—which meant universal native adult male franchise and a commitment to the principles of equal votes and freedom of speech and association. The Greek word demokratia asserted a fact and an aspiration: The people (demos) have the capacity (kratos) to make history.Aristotle (384-322 B.C.) inhabited a world of dense, urban populations and vast trade in food and labor. By his time, perhaps half of all Greek city-states were democracies, and the philosopher opined that, "now that city-states are even larger, it is difficult for any non-democratic regime to arise." Wealth was not concentrated at the top: Laborers (citizens, foreigners and slaves alike) commanded wages far above subsistence. Archaeological excavations show that even the houses of those in the lowest quartile of income were spacious and well built. In Athens, citizens promoted ever more open access through new forms of constitutional and commercial law. They supported centers of higher education that laid the foundations of Western thought: first Plato's Academy and Isocrates' school of rhetoric; then Aristotle's Lyceum, Zeno's Stoa and Epicurus' Garden. Socrates, the central figure of Bettany Hughes's delightful, if occasionally exasperating, book, was born in 469 B.C.—a long generation after Athens's democratic revolution—and died in 399 B.C., two generations before the Greek world reached its apex of population, economic success and democratization. Yet his Athens was already experiencing what can be considered a golden age of advancements in thought, art and politics. During Socrates' lifetime, the city also built and lost an Aegean empire that, at its height, encompassed more than 150 communities: a quarter-million Athenian residents and perhaps three times as many of their fellow Greeks.

Ms. Hughes presents a high-octane account of Socrates and his age, based on ancient literary sources, current archaeology and her own fertile imagination. She offers vivid slices of imagined Athenian life, taking us behind the public realm dominated by citizen men and exploring the lives of women, slaves and foreign residents in Socrates' city. Her biographical sketches of key figures— Pericles, the courtesan Aspasia, the military commander Alcibiades—are rich with lively detail. Here is Ms. Hughes on a religious sanctuary frequented by Athenian girls: "This sacred zone would have resembled an outpost of the rag-trade: when women died in childbirth their clothes were dedicated here; draped, hung and stored around the sanctuary; a limp gift to pitiless Artemis, to whom, probably just a few years from now, the girls would be calling out during the dreadful pangs of labor." Ms. Hughes weaves a morality tale about the danger of mixing politics with empire, wealth and religion, which ends with the trial of Socrates and the eclipse (she claims) of Athens' democratic golden age. Though Ms. Hughes celebrates the Socratic ideal—the idea that a constantly examined life, devoted to seeking the good and true, is the only life worth living—she does not pretend to present new insights into Socratic thought. The payoff comes, instead, through re-situating the origins of moral philosophy in the context of a vibrant cultural and historical milieu. She invites the reader to travel as her companion beyond the familiar byways of Greek history, offering a full menu of "you were there" sounds, smells and textures: noisy Eleusinian cults, stinking excrement, "the dark, the whispers, the unseen skin pricks connecting flesh to flesh" at a symposium. All of this is great fun.

Yet readers must proceed with caution, for her conclusions are questionable. Athenian greatness, for Ms. Hughes, is coterminous with Socrates' life. "Socrates' lifespan marked the beginning and an end of an idea—the idealistic vision of an autonomous, tolerant, democratic Athenian city-state," she writes. Aristotle, who was born 15 years after Socrates' death and lived in a wealthy, densely populated Greek world in which democracy was increasingly prevalent, would be puzzled by Ms. Hughes's conclusions. But precipitous rises and tragic falls tend to be attractive to popular historians. Even more problematic is that Ms. Hughes fails to provide a convincing answer to the central question of her tale: Why was Socrates tried and condemned? Socrates was a public philo sopher who could reliably be found conducting dialogues near the bankers' tables in the Agora. But he was also known to contemporaries as a teacher of aristocrats—including Alcibiades and Critias, who became enemies of the Athenian democracy, the latter in a blood-drenched postwar coup d'état in 404-03 B.C. Protected by an amnesty, Socrates could not be prosecuted for having taught the tyrant Critias to despise democracy. But the philosopher's behavior following the democratic restoration was not similarly protected—and both before and after the coup his behavior included engaging others in public dialogues. Athenians had always held citizens legally responsible for the effects of their public speech. Socrates' dialogues were intended to make his listeners behave differently, and he denied that good ideas ever produced bad behavior. But the monstrous acts of Critias (among others) seemed evidence to the contrary.

And so Socrates' accusers were free to claim that, whether he realized it or not, he was a public danger, especially to impressionable youths. Since his public speech included sharp criticism of demo cracy, they could imply that Socrates, in effect, handed out knives to madmen, that when he denied dialogue could ever be dangerous Socrates was disingenuous or deluded, that his irresponsible speech was likely to have bad effects in the future—as it seemingly had in the past.The charge brought against Socrates, by a team of voluntary prosecutors, was impiety—they accused him of impropriety in respect to the gods and corruption of the youth. I would suggest that Socrates was convicted not because the jurors were religious fanatics, not because they had lost their democratic tolerance, but because he seemed to them unreasonably unwilling to take responsibility for what he said in public. Today we allow pundits to say what they please, even if their speech has pernicious or even fatal effects. I think we are right to do so, and I think that 280 (out of 501) Athenian jurymen were wrong when they voted to condemn Socrates. But I think they were right to believe that when prominent public figures refuse to take personal responsibility for the consequences of their speech, democracy is in grave danger.

The Hemlock Cup: Socrates, Athens and the Search for the Good Life

By Bettany Hughes
Knopf, 484 pages, $35

Beyond her failure to convincingly interpret Socrates' trial, Ms. Hughes gets some facts wrong: The Athenian population did not increase five-fold during Socrates' life; nor did Athens lose four-fifths of its population during the Peloponnesian War. Papyrus does not rot within weeks in the Greek climate. Socrates' main weapon as a soldier in the Athenian army was not a broad-sword. Pericles was never elected "chief democrat." The walls of Athens did not separate citizen-haves from non-citizen have-nots. And far from despising the disabled, Athens paid handicapped citizens a daily wage.Ms. Hughes is also too uncritical of her sources: She offers late Roman accounts of the Athenian persecution of intellectuals, long ago rejected as tendentious fictions by serious scholars, as fact and even inflates them into a systematic regime of censorship, book-burning and execution. She imagines that "scores— perhaps hundreds" of intellectuals shared Socrates' fate. If this were true, Socrates' trial would be unsurprising, but Ms. Hughes's claim is not supported by any credible evidence. All the same, and despite these glitches, do read this book, both because of its marvelous storytelling and because it will stimulate a desire to learn more about the ancient world. Ms. Hughes's work joins a growing shelf of books about antiquity that exemplify the honorable goal of responsible popularization. Readers attracted to the splendid range of classical texts excerpted by Ms. Hughes will want to read the full versions; almost all are available in modern translations. (Start with Plato, in the complete edition from Hackett, edited by John Cooper—superb translations, with helpful introductions by one of the world's leading experts.) Socrates would be pleased if his story awakened a few modern Americans from moral slumber.

—Mr. Ober, chairman of political science and professor of classics at Stanford, is author of "Democracy and Knowledge: Innovation and Learning in Classical Athens."